Before commit a325725633c2 ("drm: Lobotomize set_busid nonsense for !pci drivers"), several DRM drivers for platform devices used to expose an explicit "drm_driver.set_busid" callback, invariably backed by drm_platform_set_busid().

Commit a325725633c2 removed drm_platform_set_busid(), along with the referring .set_busid field initializations. This was justified because interchangeable functionality had been implemented in drm_dev_alloc() / drm_dev_init(), which DRM_IOCTL_SET_VERSION would rely on going forward.

However, commit a325725633c2 also removed drm_virtio_set_busid(), for which the same consolidation was not appropriate: this .set_busid callback had been implemented with drm_pci_set_busid(), and not drm_platform_set_busid(). The error regressed Xorg/xserver on QEMU's "virtio-vga" card; the drmGetBusid() function from libdrm would no longer return stable PCI identifiers like "pci:0000:00:02.0", but rather unstable platform ones like "virtio0".

Reinstate drm_virtio_set_busid() with judicious use of

git checkout -p a325725633c2^ -- drivers/gpu/drm/virtio

Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Daniel Vetter daniel.vetter@intel.com Cc: David Airlie airlied@redhat.com Cc: Emil Velikov emil.l.velikov@gmail.com Cc: Gerd Hoffmann kraxel@redhat.com Cc: Gustavo Padovan gustavo.padovan@collabora.co.uk Cc: Hans de Goede hdegoede@redhat.com Cc: Joachim Frieben jfrieben@hotmail.com Cc: stable@vger.kernel.org Reported-by: Joachim Frieben jfrieben@hotmail.com Fixes: a325725633c26aa66ab940f762a6b0778edf76c0 Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1366842 Signed-off-by: Laszlo Ersek lersek@redhat.com Reviewed-by: Emil Velikov emil.l.velikov@gmail.com --- drivers/gpu/drm/virtio/virtgpu_drm_bus.c | 10 ++++++++++ drivers/gpu/drm/virtio/virtgpu_drv.c | 1 + drivers/gpu/drm/virtio/virtgpu_drv.h | 1 + 3 files changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drm_bus.c b/drivers/gpu/drm/virtio/virtgpu_drm_bus.c index 7f0e93f87a55..88a39165edd5 100644 --- a/drivers/gpu/drm/virtio/virtgpu_drm_bus.c +++ b/drivers/gpu/drm/virtio/virtgpu_drm_bus.c @@ -27,6 +27,16 @@

#include "virtgpu_drv.h"

+int drm_virtio_set_busid(struct drm_device *dev, struct drm_master *master) +{ + struct pci_dev *pdev = dev->pdev; + + if (pdev) { + return drm_pci_set_busid(dev, master); + } + return 0; +} + static void virtio_pci_kick_out_firmware_fb(struct pci_dev *pci_dev) { struct apertures_struct *ap; diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c index c13f70cfc461..5820b7020ae5 100644 --- a/drivers/gpu/drm/virtio/virtgpu_drv.c +++ b/drivers/gpu/drm/virtio/virtgpu_drv.c @@ -117,6 +117,7 @@ static const struct file_operations virtio_gpu_driver_fops = {

static struct drm_driver driver = { .driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_PRIME | DRIVER_RENDER | DRIVER_ATOMIC, + .set_busid = drm_virtio_set_busid, .load = virtio_gpu_driver_load, .unload = virtio_gpu_driver_unload, .open = virtio_gpu_driver_open, diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h index b18ef3111f0c..acf556a35cb2 100644 --- a/drivers/gpu/drm/virtio/virtgpu_drv.h +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h @@ -49,6 +49,7 @@ #define DRIVER_PATCHLEVEL 1

/* virtgpu_drm_bus.c */ +int drm_virtio_set_busid(struct drm_device *dev, struct drm_master *master); int drm_virtio_init(struct drm_driver *driver, struct virtio_device *vdev);

struct virtio_gpu_object {